In many situations in the prior art, as in for example, turbine engine fuel controls, a gauged or sensed flow through fluid pressure is employed for in turn conveying a signal pressure to related apparatus which appropriately respond thereto. That is, some circumstances, again with respect to turbine engine fuel control systems for example, an engine operating parameter may be sensed in the form of a variable magnitude fluid pressure which varies to be indicative of such operating parameter. Such fluid pressure may, in turn, be directed to associated apparatus which, for example, may respond thereto in a manner whereby a reduction in the magnitude of the fluid pressure sensed by such associated apparatus causes such associated apparatus to react by dictating that an increased rate of fuel flow should be delivered to the engine.
Quite often in such systems employing pressurized fluid flow, suitable filter means must be provided as to continuously filter dirt and foreign particles from the flowing pressurized fluid. Where such filter means are provided, for example, upstream of the said associated apparatus, problems have occurred because as the filter becomes progressively clogged with filtered dirt, the filter creates an increasing pressure drop thereacross with the result that the said associated apparatus senses what it believes to be an actual reduction in the magnitude of the pressurized fluid caused by a change in the engine operating parameter and consequently results in a greater rate of fuel flow to the engine whereas, in reality, the actual reduction in magnitude of pressurized fluid was due solely to the filter becoming clogged with dirt. In such situations, the erroneously increased rate of fuel flow may well be damaging to the engine.
Accordingly, the invention as herein disclosed and described is primarily directed to the solution of the above as well as other related problems.